http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
InGaN LED에서 칩 구조 및 칩마운트 구조에 따른 광추출효율에 관한 연구
이성재,Lee, Song-Jae 한국광학회 2005 한국광학회지 Vol.16 No.3
InGaN LED에서 칩 구조 및 칩마운트 구조에 따른 광추출효율의 변화를 Monte Calo 기법을 이용하여 해석하였다. Simulation을 통해 얻은 중요한 결론의 하나는, InGaAlP 또는 InGaN/SiC LED의 경우에서는 달리, InGaN/sapphire LED의 경우 칩의 측 벽면 기울임 기법의 광추출효율 개선효과가 상대적으로 미미하다는 점이다. InGaN/SiC LED의 경우와는 달리, 기판으로 사용되는 sapphire의 굴절률이 상대적으로 작아서 생성된 광자들이 기판으로 넘어가는데 전반사장벽을 만나게 되어, 많은 광자들이 기판으로 넘어가지 못하고 두께가 매우 얇은 반도체 결정층에 갇히는 현상 때문이다. 동일한 현상은 epi-down 구조의 칩 마운트에서 광추출효율이 크게 개선되지 못하는 원인으로도 작용하게 된다. 광추출효율 관점에서의 epi-down 구조의 InGaN/sapphire LED가 갖고 있는 잠재력을 살리기 위한 방법의 하나는 기판-에피택시 계면을 texturing 하는 것이라고 할 수 있는데, 이 경우 생성된 광자들이 다량기판으로 넘어갈 수 있게 되어 광추출효율이 현저하게 개선된다. The performance of the InGaN LED's in terms of the photon extraction efficiency has been analyzed by the Monte Carlo photon simulation method. Simulation results show that the sidewall slanting scheme, which works well for the AlInGaP or InGaN/SiC LED, plays a very minimal role in InGaN/sapphire LED's. In contrast to InGaN/SiC LED's, the lower refractive index sapphire substrate restricts the generated photons to enter the substrate, minimizing the chances for the photons to be deflected by the slanted sidewalls of the epitaxial semiconductor layers that are usually very thin. The limited photon transmission to the sapphire substrate also degrades the. photon extraction efficiency especially in the epitaxial-side down mount. One approach to exploit the photon extraction potential of the epitaxial-side down mount may be to texture the substrate-epitaxy interface. In this case, randomized photon deflection off the textured interface directly increases the number of the photons entering the sapphire substrate, from which they easily couple out of the chip and thereby improving the photon extraction efficiency drastically.
이성재,송재원,신상영,Lee, Seong-Jae,Song, Jae-Won,Sin, Sang-Yeong 대한전자공학회 1984 전자공학회지 Vol.21 No.3
Submicron gratings are fabricated holographically on thin film single mode and multimode waveguides. Thin film waveguides are made by spin-coating polyurethane solution on the substrates of microscope slide glass and Corning 7059 glass. In order to characterize thin film waveguides, the refract사e index and the thickness of thin films are measured by using the m-line spectroscopy. The fabricated gratings are tested as a grating coupler, a mode converter, and a beam splitter. Also chirped gratings are fabricated to observe beam expansion phenomena and thus the possibility of the wavelength demultiplexing.
이성재,신충훈,최소영,이동형,유순미,송흥권,윤인하,Lee Sung Jae,Shin Chung Hun,Choi So Young,Lee Dong Hyeong,Yoo Soon Mi,Song Heung Gwon,Yoon In Ha 대한방사선치료학회 2022 대한방사선치료학회지 Vol.34 No.-
Purpose: The purpose of this study is to evaluate the effectiveness of reducing the absorbed dose to the ovaries and the quality of the CBCT image when using the Halcyon<sup>TM</sup> Fast kV CBCT of cervical cancer patients of child-bearing age who performed ovarian transposition Materials and Methods : Contouring of the cervix and ovaries required for measurement was performed on the computed tomography images of the human phantom (Alderson Rando Phantom, USA), and three Optically Stimulated Luminescence Dosimeter(OSLD) were attached to the selected organ cross-section, respectively. In order to measure the absorbed dose to the cervix and ovaries in the Truebeam<sup>TM</sup> pelvis mode (Hereinafter referred to as TP), The Halcyon<sup>TM</sup> Pelvis mode (Hereinafter referred to as HP) and The Halcyon<sup>TM</sup> Pelvis Fast mode (Hereinafter referred to as HPF), An image was taken with a scan range of 17.5 cm and also taken an image that reduced the Scan range to 12.5cm. A total of 10 cumulative doses were summed, It was replaced with a value of 23 Fx, the number of cervical cancer treatments, and compared In additon, uniformity, low contrast visibility, spatial resolution, and geometric distortion were compared and analyzed using Catphan 504 phantom to compare CBCT image quality between equipment. Each factor was repeatedly measured three times, and the average value was obtained by analysing with the Doselab (Mobius Medical Systems, LP. Versions: 6.8) program. Results: As a result of measuring absorbed dose by CBCT with OSLD, TP and HP did not obtain significant results under the same conditions. The mode showing the greatest reduction value was HPF versus TP. In HPF, the absorbed dose was reduced by 39.8% in the cervix and 19.8% in the ovary compared to the TP in the scan range of 17.5 cm. the scan range was reduced to 12.5 cm, absorbed dose was reduced by 34.2% in the cervix and 50.5% in the ovary. In addition, result of evaluating the quality of the image used in the above experiment, it complied with the equipment manufacturer's standards with Geometric Distortion within 1mm (SBRT standard), Uniformity HU, LCV within 2.0%, Spatial Resolution more than 3 lp/mm. Conclusion: According to the results of this experiment, Halcyon<sup>TM</sup> can select more various conditions than Truebeam<sup>TM</sup> in treatment of fertility woman who have undergone ovarian Transposition , because it is important to reduce the radiation dose by CBCT during radiation therapy. So finally we recommend Halcyon<sup>TM</sup> Fast kV CBCT which maintains image quality even at low mAs. However, it is consider that the additional exposure to low doses can be reduced by controlling the imaging range for patients who have undergone ovarian transposition in other treatment machines.
비선형 점탄성 부싱모델의 회전방향모드에 대한 실험적 연구
이성범 ( Seong Beom Lee ),이성재 ( Sung Jae Lee ),전성철 ( Sung Chul Jun ),송동률 ( Dong Ryul Song ),정재영 ( Jae Young Jeong ),박찬석 ( Chan Seok Park ),이우현 ( Woo Hyun Lee ) 한국고무학회 2008 엘라스토머 및 콤포지트 Vol.43 No.1
자동차 부싱은 차체로 전달되는 하중을 줄여주는 역할을 하는 자동차 현가장치의 주요부품으로 바깥쪽 슬리브와 안쪽의 축 사이에서 가운데가 비어 있는 실린더의 형상을 가진다. 차축에 작용되는 힘과 모멘트에 대한 부싱의 상대변위 및 변형각도는 점탄성 성질을 나타내며, 부싱에서 힘과 모멘트와 이에 대한 변위와 변형각도의 관계는 다물체 동역학 시뮬레이션에 매우 중요하다. 본 연구는 자동차 부싱의 회전방향 모드에 대한 모멘트와 변형각도의 점탄성 관계를 변형각도에 의존하는 모멘트 완화함수를 통하여 부싱모델을 완성하였으며, 완성된 점탄성 부싱 모델은 회전방향 모드에 대한 실험값과 비교하여 검증하였다. A bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force and moment applied to the shaft and the relative deformation and rotational angle of a bushing exhibits features of viscoelasticity. Since a moment-rotational angle relation for a bushing is important for multibody dynamics numerical simulations, the simple relation between the moment and rotational angle has been derived from experiment. It is shown that the predictions by the proposed moment-rotational angle relation are in very good agreement with the experimental results.
Fluorine 주입에 따른 NMOSFET의 소자 특성 연구
권성규,권혁민,이환희,장재형,곽호영,고성용,이원묵,이성재,이희덕,Kwon, Sung-Kyu,Kwon, Hyuk-Min,Lee, Hwan-Hee,Jang, Jae-Hyung,Kwak, Ho-Young,Go, Sung-Yong,Lee, Weon-Mook,Lee, Song-Jae,Lee, Hi-Deok 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.1
In this paper, we investigated the device performance on fluorine implantation, hot carrier reliability and RTS (random telegraph signal) noise characteristics of NMOSFETs. The capacitance of the fluorine implanted NMOSFET decreased due to the increase of the gate oxide thickness. RTS noise characteristics of the fluorine implated NMOSFET was improved approximately by 46% due to the decrease of trap density at Si/$SiO_2$ interface. The improved gate oxide quality also results in the longer hot carrier life time.
곽호영,권혁민,권성규,장재형,이환희,이성재,고성용,이원묵,이희덕,Kwak, Ho-Young,Kwon, Hyuk-Min,Kwon, Sung-Kyu,Jang, Jae-Hyung,Lee, Hwan-Hee,Lee, Song-Jae,Go, Sung-Yong,Lee, Weon-Mook,Lee, Hi-Deok 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.12
In this paper, reliability of the two sandwiched MIM capacitors of $Al_2O_3-HfO_2-Al_2O_3$ (AHA) and $SiO_2-HfO_2-SiO_2$ (SHS) with hafnium-based dielectrics was analyzed using two kinds of voltage stress; DC and AC voltage stresses. Two MIM capacitors have high capacitance density (8.1 fF/${\mu}m^2$ and 5.2 fF/${\mu}m^2$) over the entire frequency range and low leakage current density of ~1 nA/$cm^2$ at room temperature and 1 V. The charge trapping in the dielectric shows that the relative variation of capacitance (${\Delta}C/C_0$) increases and the variation of voltage linearity (${\alpha}$/${\alpha}_0$) gradually decreases with stress-time under two types of voltage stress. It is also shown that DC voltage stress induced greater variation of capacitance density and voltage linearity than AC voltage stress.
Plasma Nitrided Oxide와 Thermally Nitrided Oxide를 적용한 NMOSFET의 Flicker Noise와 신뢰성에 대한 비교 분석
이환희,권혁민,권성규,장재형,곽호영,이성재,고성용,이원묵,이희덕,Lee, Hwan-Hee,Kwon, Hyuk-Min,Kwon, Sung-Kyu,Jang, Jae-Hyung,Kwak, Ho-Young,Lee, Song-Jae,Go, Sung-Yong,Lee, Weon-Mook,Lee, Hi-Deok 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.12
In this paper, flicker noise characteristic and channel hot carrier degradation of NMOSFETs with plasma nitrided oixde (PNO) and thermally nitrided oxide (TNO) are analyzed in depth. Compared with NMOSFET with TNO, flicker noise characteristic of NMOSFET with PNO is improved significantly because nitrogen density in PNO near the Si/$SiO_2$ interface is less than that in TNO. However, device degradation of NMOSFET with PNO by channel hot carrier stress is greater than that with TNO although PMOSFET with PNO showed greater immunity to NBTI degradation than that with TNO in previous study. Therefore, concurrent investigation of the reliability as well as low frequency noise characteristics of NMOSFET and PMOSFET is required for the development of high performance analog MOSFET technology.
MIM 구조를 갖는 Al<sub>2</sub>O<sub>3</sub>/HfO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> 캐패시터의 정합특성 분석
장재형,권혁민,정의정,곽호영,권성규,이환희,고성용,이원묵,이성재,이희덕,Jang, Jae-Hyung,Kwon, Hyuk-Min,Jung, Yi-Jung,Kwak, Ho-Young,Kwon, Sung-Gyu,Lee, Hwan-Hee,Go, Sung-Yong,Lee, Weon-Mook,Lee, Song-Jae,Lee, Hi-Deok 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.1
In this paper, matching characteristic of MIM (metal-insulator-metal) capacitor with $Al_2O_3/HfO_2/Al_2O_3$ (AHA) structure is analyzed. The floating gate capacitance measurement technique (FGMT) was used for analysis of matching characteristic of the MIM capacitors in depth. It was shown that matching coefficient of AHA MIM capacitor is 0.331%${\mu}m$ which is appropriate for application to analog/RF integrated circuits. It was also shown that the matching coefficient has a more strong dependence on the width than length of MIM capacitor.
척추견인 시스템의 인체 역학적 견인력에 대한 이론적 고찰 및 구현에 관한 연구
장호종,이성재,Chang, Hojong,Lee, Song Jae 대한의용생체공학회 2014 의공학회지 Vol.35 No.2
According to recent data more than 80% of people suffer from back pain, due to an aging and a poor posture, at least once in their life time, and 7~10% of them have chronic spine illness. Researchers over the years have studied on various spinal traction devices that utilize the force of traction, and have also reported clinical test results. However, most existing devices are too complicated and too expensive. In order to solve these problems, we have developed a new device in which the frame moves up and down and at the same time tilting angle of the frame is adjusted. We have analyzed the forces applied on the body as a function of tilting angle. And the result shows that the new device has achieved the force of traction, which is known to be effective for spinal rehabilitation.